Creating a delayed blur effect?
I don't have an elegant solution but it seems to work. Instead of fading a frame, I just use 8 or more strips with the same image sequence and move them each one frame to the right.

Each of the strips (except the bottom one) gets a transform strip. There I lower the opacity and move the strip a bit with the position fields.

You might need to use a gaussian blur strip, too.

It looks a bit better if the Blend type is set to 'add'